Liver Fluke - The Accidental Smallholder

Fasciola hepatica (Liver fluke) is a serious parasite of both sheep and cattle; unlike worms, it is not host specific but affects a number of species. Liver fluke also has quite a complex lifecycle, which includes a water snail as an intermediate host so resting pasture doesn’t necessarily have the same effect on fluke as on worms.

A further problem with fluke is that its presence doesn’t always show up in faecal worm egg counts – it depends on whether it is at the egg-shedding stage of its lifecycle and the since the adult fluke maybe only releases one egg a day, the chances of it being in that wee sample are pretty slim.

The “fluke season” is usually held to be October to March but changing climate patterns – warmer and wetter - mean that the season may be lengthening and the impact of fluke growing.

The presence of the water snail in the lifecycle used to mean that liver fluke has traditionally been held to be more of a problem on the wetter West side of the UK, but these climate changes, though, has meant that it is now an increasing problem in the eastern areas too. Your vet will be able to advise on whether fluke is a problem in your area.

There are also issues of resistance to some flukicides. Triclabendazole is a common flukicide that is now experiencing resistance in some areas but other flukicides such as closantel are now available. Flukicides are usually a drench and some have a lengthy withdrawal period – up to eight weeks.

If you are sending cattle or sheep direct to slaughter, it’s worth getting a report back on the livers; although livers can be condemned for reasons other than fluke infestation, it’s useful intelligence to have.

It is possible to reduce the danger from fluke by removing the intermediate host, the water snail. Good drainage can help by removing habitat; otherwise fence off wet areas, although this often is practical on limited grazing. There are chemical sprays are available that kill the snail.  Running ducks on the pasture is sometimes suggetsted, on teh premise that they eat the snails, but these water snails are microscopic - not big, fat, juicy garden snails - so I'm more than a little sceptical about this.

We routinely dose with flukicide before tupping in October, at scanning in January and after lambing, when we turn out the ewes with their new lambs. This spring dose can help to reduce the amount of new infection on pastures in the following autumn.

We use triclabendazole in October, which kills all stages of fluke, and closantel in January and April."